New Garrett Gt3540 Internal Gate Is Here + Dyno Results

[discopotato03]

Hands strictly above the desk Joel !

[garage-tuner]

where did you get that info from?

cheers

From MTQ Engine Systems.

Cheers.

PS Nice work on the photos Disco!!

[dangerman4]

its all on and running smooth.

i need a tune as knock starts heading towards 90, but at 13 psi it pulls like a train.

very smooth power.

like the falcon xr6 turbo just with lag.

havent done enough kays as yet to work out when boost hits etc. but id say around 4500 things start to happen fairly quickly.

[Rolls]

Sorry if this has been answered before but what are the advantages of an internal gate over an external gate, aside from the obvious cost factor.

Edited September 15, 2006 by Rolls

[Cubes]

Disco

Thanks for the pics buddy.. You know I'm a Pic man.

------------

Rolls

Pros:

Compact & cost saving

Cons:

If the internal gate hasn't been designed correctly its quite possible boost will creep at higher boost pressures.

Boost creep is where the wastegate is unable to pass enough exhaust gas to keep boost at its preset level, as a result boost continues to rise uncontrollably. Boost creep will usually occur if one attempts to run the higher boost levels.

For example you may be able to hold 15psi perfectly but upping the boost to 18psi may see boost creep 18, 19, 20psi as revs increase.

Thats my understanding.

[Busky2k]

My impression was that external gates are better than an internal because you are introducing the wastegate gases separately back into the exhaust (or not for a 'screamer') which is a power adder. Moreover, the 'waste' exhaust gases do not have to enter the turbine housing at all and instead are diverted from the manifold side, also decreasing the backpressure/turbulence in the scroll I believe. And finally, you are getting superior boost control with an appropriately sized gate.

[Dale FZ1]

you are getting superior boost control with an appropriately sized gate.

That is the real key - the size of the valve is significantly larger; more bypass flow = better control.

[Cubes]

That’s only if it is required...

If you can size the internal gate appropriately then there really is no benefit with the use of an external gate.

Of which Dangerman is soon to find out once he dials in 20 psi.

My guess is he will need to pull the turbo off again and do the usual XR6 wastegate mod. Hopefully not.

Hell its a built motor, let it have 30psi.

[Abo Bob]

Can I ask why the spacer is necessary? Could you use this turbo with a standard manifold?

Its my opinion only but a .63 housing on this turbo is too small given its air pumping capacity , if the .82 is too laggy its trying to tell you its too much turbo - or compressor anyway . If smaller trim compressors were available in this turbo it may just work . Another maybe is to use port shrouded compressor covers to avoid the surge issue .

RB30DET's seem to handle the 1.06 ok and even the .82 for a roadie that does not use huge boost pressures . I hear people say that it works ok on RB26's as well though they are probably expected to lift their skirts at 4000+ rpm . I guess a serious track Rb25 with gearing etc to suit could use a .82 version . Gary and others have said that even GT3076R's can be a bit much on a daily driven RB25DET so the GT3540R being larger could be expected to have a higher boost threshold . This is normal when comparing a 500 to a 700Hp capable turbocharger . Power numbers are impossible to quote because the same turbo will give vastly different results on a real race engine compared to the production version it was based on . You can base turbo power potential off the maximum airflow it can efficiently pump (this is usually expressed as pounds per minute) though exhaust flow and turbine efficiency is just as important .

Out of here now , need some sleep (I know how Roy feels) .

Cheers A .

You're always so grey Adrian. Bite the bullet and say it. It's a BIG turbo for an RB25. You would want an at least 8000rpm redline to make use of the power it's making. If the 0.82 housing is too laggy for you then make Dangerman an offer on his old GT30.

Shonen - it's not necessary to high mount it so you don't want it.

And to whoever asked what that turbo was beside it, I'm guessing that's the GT30 he took off.

I am very interested in seeing how laggy it turns out to be.

[dangerman4]

Can I ask why the spacer is necessary? Could you use this turbo with a standard manifold?

no... my stainless low mount gives me more room then the standard manifold and i still needed to space

it 25mm.

it is just to big.

1.5 hours on a mill and 25mm spacer is complete.

And to whoever asked what that turbo was beside it, I'm guessing that's the GT30 he took off.

yes its the gt30..

I am very interested in seeing how laggy it turns out to be.

i have noticed going up a hill at 3000rpm in drive its allready making 5psi.

and thats with the boost controller turned off.

once i dial in 20 pound it should improve on that.

[discopotato03]

Can I ask why the spacer is necessary? Could you use this turbo with a standard manifold?

You're always so grey Adrian. Bite the bullet and say it. It's a BIG turbo for an RB25. You would want an at least 8000rpm redline to make use of the power it's making. If the 0.82 housing is too laggy for you then make Dangerman an offer on his old GT30.

Shonen - it's not necessary to high mount it so you don't want it.

And to whoever asked what that turbo was beside it, I'm guessing that's the GT30 he took off.

I am very interested in seeing how laggy it turns out to be.

Nah , copper tops get a bit of salt and pepper rounds the hackles but no grey !

Yep , big for street RB25 but some like them that way - not for me to judge .

Don't know about the 8000rpm bit , an RB25 in basic terms is just a more conventional or less competition oriented RB26 with 60 odd less cc's and one turbo . If it pulled up at 4000 that makes a 4000 rpm wide power range assuming you were going to go to 8 .

No GT30's dont have the exhaust flow I'm after and unless the 52 comp trim GT3037 (HKS option only) was used the flow ratios are not good enough in my book . GT3540R is basically a scaled up GT3076R (real GT30R) . I'm not saying they're a bad thing is just I think there may be better (not off the shelf) options for a low boost setup on an RB31DET . The GT35 turbine is quite good though still Garretts older thinking of big or 84 trim . I'm going to hold out for (at this stage) the GT37R turbine which is a tad larger (72.5 vs 68mm) but in 78 trim rather than 84 . The 82mm 50 trim comp would be a doddle for such a turbine to drive so should make for good performance with very little exhaust restriction . I'm hoping to have a scaled up GT28RS or discopotato (that echo again) but for 3L rather than 2L . Bullocks Taters ?

At this stage the turbine housing (GT37R) is huge and heavy but if it was assembled in a TO4Z bearing housing (basically same but clamps to exhaust housing instead of 4 bolt/ear type ie GT4088R) housing options could be TO4 or GT35 type .

Will post some pics of elusive GT37R but OT in this string .

Cheers A .

[ZILR-34]

how would the Garrett Gt3540 with the .63 rear go on a rb20det? would it be lagy?

[Busky2k]

^^. Laggy would be an understatement.

[dangerman4]

can any one recomend any decent back tyres to run on the dyno.

do M/T street radials work well.

[drag-on silvia]

time for an update. how did it go on the dyno????

[dangerman4]

time for an update. how did it go on the dyno????

im booked in for friday at 11:00am

tomorrow night i will install a 044 intank, so my only limiting factor will be the standard coil packs.

they have only done 47,000 klm's so shouldnt be to bad.

hopefully the pump install goes to plan, and i will put up all my findings friday arvo.

[T-u-R-b-O]

what about the MAF?

[discopotato03]

how would the Garrett Gt3540 with the .63 rear go on a rb20det? would it be lagy?

Very much so . Would show up the RB20's lack of torque in essentially low CR form . If Garrett get around to making the GT30 IW exhaust housings in .63AR ratio then the real GT3071R would be a much better thing . HKS's GT2835 Pro S could be Ok but expensive , 3071R a better thing IMO .

As Joel mentioned IW exhaust housings need to be properly designed for high performance petrol applications . HKS's Pro S housings are probably the best for the GT30 turbines but not cheap . Truthfully the combination of compressor and turbine have a large say in potential wastegate problems . Its this holey grail of equal turbine inlet pressure and boost pressure that lets the waste gate regulate properly .

Main problem with RB20's is that they're right on the cusp of GT28 and GT30 turbines flow wise . HKS seemed to nail it with their cropped version of the GT30 turbine but dropped the ball with compressor choise . Had they asked Garrett to make a GT30 turbine based cartridge with a smaller turbine trim ie 76-78 instead of the garden variety 84 trim the GT30 based turbos would be very responsive with small to mid trim 71mm or GT35 series compressors .

I guess the expensive nature of the Pro S series turbos made HKS err towards the larger compressor trims , sort of more bucks for more power potential . I think they expect most RB20 people to be happy with GT28 turbine based turbos and the rest go with 2835's or GT3037's etc . It is possible to bitzer together a good turbo based on Garrett guts and HKS exhaust housing but not cost effective and O/T in this thread .

Cheers A .

[Abo Bob]

Very much so . Would show up the RB20's lack of torque in essentially low CR form . If Garrett get around to making the GT30 IW exhaust housings in .63AR ratio then the real GT3071R would be a much better thing . HKS's GT2835 Pro S could be Ok but expensive , 3071R a better thing IMO .

Is there anything that can be done for the RB20 guys with all the excess 0.63AR exhaust housings from HKS GT2835 ProS? There are a lot of these things around because that's the one that comes with the kit. A lot of people get them for their RB25's and then find out the hard way that the exhuast housing is too small. At great expense they get the 0.87 rear thus 0.63 rears sitting on shelves in quantities.

[The Mafia]

I'm jumping in this thread for more info.

Still trying to work out what to do with my turbo.

oh, and for those that where talking about dump pipes before. Were you talkingabou something like this

Edited September 21, 2006 by The Mafia